The early work on opinion target detection from on-line reviews presented by [1]} used association rule mining based on Apriori algorithm [2]} to extract frequent noun phrases as product features. For polarity detection, they used two seed sets of 30 positive and negative adjectives, then WordNet has been used to find and add the synonyms of the seed words. Infrequent product features or opinion targets had been processed by finding the noun related to an opinionated word.
